Diego Costa was set to have his knee assessed on Thursday after scoring but suffering an injury in the first match of his latest spell with Atletico Madrid.
The former Chelsea striker netted after coming off the bench midway through the second half of Wednesday’s 4-0 Copa del Rey away win against Lleida.
Costa, 29, grabbed Atletico’s third goal of the evening just five minutes after his introduction.
But in doing so he also sustained an injury to his right knee, seeming to jar his leg as he slid in to convert a low cross from the right.
Costa was treated on the pitch and was able to continue.
Atletico later stated on their website: “During Thursday’s training session, the medical staff will determine if it’s necessary for the striker to undergo medical exams.”
Despite the knee worry, Brazil-born Spain international Costa was enthusiastic about his return to the club he first joined in 2007.
Costa was farmed out to several clubs when he arrived at Atletico over a decade ago, before eventually pinning down a first-team place and landing a lucrative move to Chelsea in 2014.
Now he is set for a key role as second-placed Atletico push for a lofty finish in LaLiga.
He said: “I’m very happy to have played for Atletico Madrid again. This was very important for me and I’m very happy.
“I can’t ask for more in this second debut for Atletico. I got to play and I was lucky enough to score. This makes me even happier.”